A saintly person regards all others to be holier than him or her. In reality, this cannot be true, but it's a great way to practice humility. You could say that going overboard provides the cushion you need. It's like an arched bridge or one of those long truck beds ~ the slight upward curve provides a lot extra strength for carrying the load, hence a greater safety factor. Similarly, being "over-humble" is a good way to become more humble.